Check valves are valves that allow fluid flow in one direction therethrough and prevent flow in the opposite direction. They are widely used in a range of applications, for example in air conditioning systems, for example in aircraft air conditioning systems.
Check valves commonly include a pair of valve elements or flappers located at an opening in a valve housing. The flappers are hingedly supported on a hinge pin mounted to the valve housing for rotation between a closed position in which they lie across and close the opening, preventing fluid flow through the opening in one direction and an open position in which, under the pressure of a fluid (gas or liquid) on one side of the check valve, the flappers rotate from their closed positions so as to allow the fluid to flow through the valve in the opposite direction.
It is has been found that in order to achieve good sealing between the flapper elements and the valve housing and also to reduce wear on opening, some vertical lift off of the flapper elements from the valve housing prior to rotation may be desirable.
The present disclosure relates to a check valve which allows for such movement.